1. Field of the Invention
The present invention relates to a device and a method for cutting out a moving image, which obtain a composite image including a movement trajectory of a moving body by composing a moving body included in each of a plurality of frames sampled from the moving image on one frame, and a program for causing a computer to execute the method for cutting out a moving image.
2. Description of the Related Art
Due to the recent popularization of digital video cameras, it is possible to handle a moving image on a per-frame basis. Moreover, a captured moving image can be imported into a personal computer to be edited and processed as necessary. Furthermore, a method has been proposed to process frames sampled from a moving image so that the movement trajectory of a moving object, in other words, a moving body, may appear in one still image (refer to Japanese Unexamined Patent Publication No. 5(1993)-316418).
In the method disclosed in Japanese Unexamined Patent Publication No. 5 (1993)-316418, differential signals between a reference signal and a plurality of input signals are calculated. The calculated differential signals are added to the reference signal in chronological order to generate composite signals. In the case where this composite signal is obtained, when the moving body overlaps with another, the signal value exceeds an upper limit value of a video signal. In order to prevent this, the differential signals, of which values are halved, are added to the reference signal.
Nevertheless, in the method, the signal used for the composition includes only the moving body without a background. Accordingly, when the method is applied to a plurality of frames, which are obtained by ordinary filming and include both backgrounds and a moving body, the moving body cannot alone be extracted from the frames. As a result, the composite signals including the movement trajectory of the moving body cannot be obtained. In addition, since the differential signals, of which values are halved, are added to the reference signal in the method, regions of the moving body overlap with the backgrounds in a composite image obtained by reproducing the composite signals. Consequently, the contrast of the moving body is reduced.